The B1661 Code is found when the car is diagnosis and it is related the car engine. It is compulsory to fix the issue for running the car properly. If you do not know the dictionary meaning, you cannot also solve the problem. It is necessary to get the meaning. From the B code, it is identified that body of the engine has the problem. The oxygen sensors on the car degree the oxygen in the finish to identify how rich or thin the ratio of fuel and air are in the car cylinders. Enhancing this combination is better fuel economy and fewer use releases.